To reveal the mechanism of influence of friction disc surface groove on transmission performance during hydro viscous drive, the calculation model of oil film bearing capacity and transmitted torque was established based on the principle of fluid dynamics, and the oil film bearing capacity, transmitted torque and temperature rise of the friction disc with different width, depth and number of grooves were numerically simulated by using software FLUENT based on the established oil film physical model. The results show that with the increase of width and depth of grooves, both of oil film bearing capacity and transmitted torque are decreased, and with the increase of the number of grooves, the oil film bearing capacity is increased and the transmitted torque is decreased linearly. The oil film temperature rise is increased gradually along the radial direction, and it can be effectively reduced by increasing the width, depth and number of grooves at constant oil film speed during transmission process.